Ear plugs are widely used devices for hearing protection. However, they have the disadvantage of being small and easily lost. This is highly objectionable in some areas of use, for example, in the food processing industry where the presence of a "lost" ear plug in a food product causes great consternation and trauma.
To reduce the chance of an ear plug becoming lost it is common to fasten two plugs together by means of a cord of sufficient length to permit the user to conveniently insert both plugs in his ears. Various methods are used to fasten cords to plugs depending upon the materials involved. One widely used ear plug, a polyvinyl chloride foam product has the cord welded to the plug by means of a thermal "spot weld".
Prior art arrangements generally related to the field of this invention include U.S. Pat. No. 2,538,339, RE No. 29,487, DES No. 245,202 and German Offenlegungsschrift No. 23 25 823.